I think it's simply to make the funding stage can easily hit the cap. If someone do believe in this project they could buy it directly through ICO, then IEO for people that did not want to make direct payment. Also they have some place for hold an IEO, this should make the success rate rise.

Have seen this duo crowdfund process lately and I dont see the reason for it. Multiple avenue may not raise fund faster and has not shown a different response, top exchanges has not struggle to raise fund, which implicate how the choice can be efficient and the fund are now considerable low, I think the valuation is high (50000 eth). They might need to defend it at early stage or rather lower it. 

The use of the IEOs was done mostly just to reach their user base and gain more public awareness of our project. It made sense financially in terms of advertising costs and reach. Lately, exchanges that are not in the top 10 have been HORRIBLE  at having successful IEOs for small projects but they still do make sense in terms of advertising.

Any success we have from IEOs not listed on a top 10 exchange will be an unexpected blessing at this point when our project still has to prove its worth.